Class TargetChain 
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Class TargetChain

public class netscape.application.TargetChain
    extends java.lang.Object
    implements netscape.application.ExtendedTarget
{
    /* Methods
     */
    public static TargetChain applicationChain();

    public synchronized void addTarget(ExtendedTarget, boolean);
    public boolean canPerformCommand(String);
    public void performCommand(String, Object);
    public synchronized void removeTarget(ExtendedTarget);
    public synchronized Target targetForCommand(String);
}
Object subclass used to locate a Target within an application that is capable of performing a specific command. When asked to perform a command, the TargetChain asks each of its potential Targets, in turn, whether or not they implement the ExtendedTarget interface, and if so, calls their canPerformCommand() method to determine whether or not they can perform the specified command. The TargetChain forwards the command on to the first object that can perform the command. The TargetChain returned by the static applicationChain() method contains the following potential Targets:
  1. Each of the Targets added using addTarget() with atFront == true
  2. The current focusedView
  3. The main Window's owner
  4. The main Window
  5. The "first" RootView
  6. The Application
  7. Each of the Targets added using addTarget() with atFront == false
The TargetChain is useful in situations where the Target that should receive a command is context sensitive. For example, a Menu item representing the "cut" command should send its command to the current selection. If an application has multiple TextFields, the TextField that should receive the command will depend upon which TextField the user has decided to edit. By setting the Menu item's Target to the application's TargetChain, the application can configure the Menu item's Target once, with the assurance that the TargetChain will locate and forward the command to the appropriate object.
See Also:
Target

Methods

applicationChain

 
  public static TargetChain applicationChain()
Returns the Application global TargetChain.

addTarget

 
  public synchronized void addTarget(ExtendedTarget target,
                                     boolean atFront)
Adds target to the TargetChain. If atFront is true,the TargetChain will query target before any of the ExtendedTargets currently in its list. Otherwise, the TargetChain will query target only after all current ExtendedTargets.

removeTarget

 
  public synchronized void removeTarget(ExtendedTarget target)
Removes target from the TargetChain (only if target was added using addTarget()).
See Also:
addTarget

targetForCommand

 
  public synchronized Target targetForCommand(String command)
Returns the first Target that performs command.

canPerformCommand

 
  public boolean canPerformCommand(String command)
Returns true if any of the TargetChain's Targets can perform command.

performCommand

 
  public void performCommand(String command,
                             Object data)
Forwards the performCommand message to the first Target in the chain that can perform command. 
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